1. Technical Field
The present invention relates to manufacturing methods for tubes, and more particularly to a method for manufacturing a stage tube from a plate.
2. Description of Related Art
Conventionally, stage tubes are manufactured by processing solid shafts into tubes having a stage outer wall and an axial channel. This traditional approach cause, however, waste of material and time as well as processing work. While casting is an alternative manufacturing method, the related process is nevertheless complicated.
Particularly, according to the current technology, it is difficult to make a tube having its middle segment diametrically greater than its two end segments.
Therefore, the conventional technology for making stage tubes is needed to be improved.